Plastic explosive compositions



United States Patent Qfitice 3,321,341 Patented May 23, 1967 3,321,341 PLASTIC EXPLOSIVE COMPOSITIONS Karl G. Ottoson, Dover, N.J., assignor to the United States of America as represented by the Secretary of the Army No Drawing. Filed Oct. 5, 1961, Ser. No. 143,254 1 Claim. (Cl. 149-19) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon.

The present invention relates to a plastic composition intended for use as a demolition or blasting explosive. Explosives of excellent plasticity having superior stability, Water-resistance, and a low freezing point are obtained using polyisobutylene as a binder in the explosive composition.

It has long been an object of the art to obtain a plastic explosive composition that is not only Water-resistant but one that retains its plasticity even at very low and high temperatures. Many additives have been combined with explosives but have not been satisfactory because the compositions fail to retain their plasticity over a wide temperature range. Furthermore, some of these additives lessened the eiiectiveness of the explosive in terms of its rate of detonation, brisance, as determined by plate dent tests and sand tests, to such a degree that they were not practical.

The primary object of this invention is to provide explosives of high strength for blasting and demolition applications and which maintain their plasticity over a wide temperature range.

A further object of this invention is to obtain a plastic explosive that is stable at elevated temperatures, Waterresistant and non-hygroscopic.

Another object of this invention is to provide an explosive composition that is relatively insensitive to impact, friction, and small arms bullet impact.

Still another object of the present invention is to ob- 4 tain an explosive composition that is plastic and moldable at temperatures as low as 65 F.

The invention can be illustrated by the following examples:

Composition (percent by wgt.)

Explosive RDX, 90% thru 100 Mesh Sieve. 15 20 70 91 TNT, 90% thru 100 Mesh Sieve c--. 25

Barium Nitrate, 90% thru 100 Mesh Sieve Talc, 90% thru 100 Mesh Sieve Zinc Oxide, 90% thru 100 mesh Sieve" Polyisobutylene, 100,000-140,000 m.w Di-(2 ethyl hexyl) sebacate Di-(2 ethyl hexyl) adipate. Petroleum Oil (SAE 10) TABLE I Composition Ratepf Denotation (meters/sec.) 6, 625 8, 040 Density, gIIL/CC 1. 40 1. 59 Plate 066 15o Density, gmJce 1. 40 1.64 Impact Test, RA. app. 2 kg. wgt. (inches) 15 19 Sand Test:

Sand crushed (g-ni.) 37. 6 55. 7 'letryl (gm) 14 10 Lead azide (gm) 1. .20 .20

When using plasticized polyisobutylene as a binder, one can prepare a variety of moldable explosive compositions by selecting the proper combinations of particles of crystalline solids. The physical and chemical properties of solids selected will, in part, determine the suitability of the resultant composition for the intended application. Solid explosives that are particularly applicable to the present invention are ammonium picrate, tetryl, cyclotetramethylene tetranitramine, cyclotrimethylenetrinitramine, and ethylene dinitramine in concentrations from 10 to percent by weight. The oxidizers used in the explosive composition are alkali metal nitrates and mannitol hexanitrate.

A preferred embodiment of my invention includes from 15 to 91 percent of a granular explosive selected from the above group; 5 to 16 percent plasticized polyisobutylene having a molecuiar weight of about 100,000 to 140,000; the balance including an oxidizer.

It has also been found to be advantageous to add to this composition inert and/or fuel additives, some of the more common ones being aluminum powder, magnesium powder, kaolin, diatomaceous earth, charcoal and starch.

Various plasticizers for polyisobutylene may be used with the explosive composition. These plasticizers include di(ethy1 hexyl) sebacate and di(ethyl hexyl) adipate. Other fatty acid esters of dicarboxylic acids are applicable to the present invention.

Obviously, many modifications and variations of the present invention are possible in the light of the above teachings. It is, therefore, to be understood, that within the scope of the appended claim, the invention may be practiced otherwise than as specifically described.

What is claimed and desired to be secured by Letters Patent of the United States is:

A plastic explosive composition consisting essentially of about:

(a) 15 to 91 percent by weight of a granular explosive selected from the grou cyclotetramethylenetetranitramine cyclotrimethylenetrinitramine ammonium picrate tetryl ethylene dinitramine (b) 5 to 16 percent by weight of plasticized polyisobutylene having a molecular weight of about 100,000 to 140,000 and plasticized with a member of the group consisting of:

di-ethyl hexyl sebacate di-ethyl hexyl adipate (c) the balance including an oxidizer selected from the group consisting of: alkali metal nitrate mannitol hexanitrate (References on following page) 3 4 References Cited by the Examiner 3,041,216 6/ 1962 Bice '14919 3,392,362 7/ 1921 Iliice et all. ii9-i9 L. DEWAYNE RUTLEDGE, Primary Examiner.

1 9 12/19 1 ong eta 9- 9 3,018,201 1/1962 Downard 5 LEON ROSDOL, CARL Q 'IE 3,024,143 3/1962 Sammons et a1 149 19 {mmmm W. T. HOUGH, Assistant Examiner. 

